Migration status and perinatal parameters in a Greek public maternity hospital: an illustration of the “healthy immigrant effect”

Abstract Background: Although socioeconomic disparities adversely affect health, studies referring to the “healthy immigrant effect” imply more favorable health outcomes in immigrants than natives. We aimed to investigate the impact of immigration on several perinatal parameters. Methods: Birth records (01/01/2010 − 31/12/2014) from a public maternity hospital in Athens, Greece were reviewed for maternal (ethnicity, age, delivery mode) and neonatal (gender, birthweight, gestational age) variables. Immigrants were classified by country of origin, according to Human Development Index. Comparison of results between Greeks and immigrants were made. Stratification by maternal age (< and ≥35 years) was conducted to test for confounding and interaction. Results: Almost one-third of 7506 deliveries applied to immigrants; 36.3% of Greeks and 19.2% of immigrants [risk ratio (RR) = 0.53, 95% confidence interval (CI) = 0.52–0.54] delivered at ≥35 years; 10.5% of Greek and 7.0% of immigrant neonates weighted <2500 g (RR = 0.67, 95% CI = 0.61–0.74); 10.9% of Greeks and 8.1% of immigrants were born <37 wks (RR = 0.74, 95% CI = 0.67–0.82); 55.7% of Greeks and 48.2% of immigrants delivered by caesarean section (RR = 0.87, 95% CI = 0.85–0.88). Conclusion: We found that immigrant women deliver at a younger age, vaginally, more mature, and heavier neonates. Furthermore, we confirmed that the protective effect of immigrant status could not be explained by maternal age only.